2. Beep API Call

• Command

      dumpbin /exports C:\Windows\System32\kernel32.dll
  

  prints a list of windows API functions available to a console application.

• The following C++ program demonstrates a loop of 500-millisecond Beeps with rising tone frequency.

• One of the APIs is a Beep function, which generates simple tone using the sound card.

• The Beep call doesn't wait for the sound card to complete the playback; the tone is generated asynchronously. To synchronize frequency display with the sound, the program pauses by calling Sleep, which waits for the duration of the tone in milliseconds.

• The std::flush output manipulator is making std::cout display the output immediately.

• Alltogether the combination of the above steps simulates a synchronous (sequential) output of the frequency and sound.

  
  #include <iostream>
  #include <windows.h>
  
  int main()
  {
      int ms = 500; // sound duration in milliseconds
      // frequency (hertz) must be in range 37 through 32767
      for ( int frequency = 500; frequency < 2000; frequency += 200 ) {
          // display sound frequency in hertz before each tone.
          std::cout << frequency << " " << std::flush;
          Beep( frequency, ms );
          Sleep( ms );
      }
      return 0;
  }